There is great need in the developing world for engineered drug delivery systems that prevent the male to female sexual transmission of HIV. To this end we are exploring the use of bioresponsive drug delivery systems, which we tailor to the physiological and mechanical requirements essential for vaginal drug delivery. These polymeric constructs are designed to incorporate controlled release characteristics, allow for enhanced tissue coating, reduced viral transport and allow for triggered release of anti-HIV drugs by interaction with semen. For example, we have triggered the release of antiviral agents by utilizing the change in vaginal pH that occurs after coitus or by seminal enzymes in the ejaculate. In this way, we believe the antiviral agents' biodistribution and bioavailability can be modulated to increase potency and allow for burst release of free HIV inhibitors at the initial onslaught of viral exposure. The design parameters, synthesis and characterization of a few of these microbicide delivery systems will be discussed.